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目的：探讨表没食子儿茶素投食子酸酯[（－）－epigallocatechin-3-gallate，EGCG]诱导胃癌MGC－803细胞和肝癌BEL－7402细胞凋亡的作用及其调亡相关基因bcl-2产物表达的改变。方法：用MTT法、琼脂糖凝胶电泳、流式细胞术检测EGCG处理MGC-803细胞和BEL-7402细胞后，他们在形态学和生化方面的改变以及bcl－2蛋白表达水平的变化。结果：EGCG以剂量依赖的方式抑制MGC－803细胞和BEL－7402细胞的生长，其IC50值分别为188．52和264．53μg／ml。200～300μg／ml的EGCG处理MGC-803细胞和BEL-7402细胞24～36h，在琼脂糖凝胶电泳上可见凋亡细胞特征性的“梯状”带和PI染色流式细胞仪直方图上可见亚二倍体峰；流式细胞术显示EGCG以时间依赖的方式下调bcl-2蛋白的表达。结论：EGCG对胃癌MGC-803细胞和肝癌BEL-7402细胞生长具有抑制作用，其机制之一是诱导这两株肿瘤细胞的凋亡。诱导细胞凋亡的机制可能与其下调bcl-2蛋白的表达水平有关。
OBJECTIVE: To investigate the effect of epigallocatechin gallate ([--]-epigallocatechin-3-gallate, EGCG) on the apoptosis of gastric cancer MGC-803 cells and hepatocellular carcinoma BEL-7402 cells and its apoptosis-related gene bcl- 2 changes in product expression. METHODS: After MGC-803 cells and BEL-7402 cells were treated with EGCG by MTT assay, agarose gel electrophoresis and flow cytometry, their morphological and biochemical changes and changes in bcl-2 protein expression levels were analyzed. RESULTS: EGCG inhibited the growth of MGC-803 cells and BEL-7402 cells in a dose-dependent manner with IC50 values of 188.52 and 264.53 μg/ml, respectively. The MGC-803 cells and BEL-7402 cells were treated with 200-300 μg/ml EGCG for 24-36 h. The agarose gel electrophoresis showed a characteristic “stepped” band of apoptotic cells and PI staining on flow cytometry histograms. Subdiploid peaks were seen; flow cytometry showed that EGCG downregulated the expression of bcl-2 protein in a time-dependent manner. CONCLUSION: EGCG has inhibitory effect on the growth of gastric cancer MGC-803 cells and hepatoma BEL-7402 cells. One of the mechanisms is the induction of apoptosis in these two tumor cells. The mechanism of apoptosis induction may be related to the down-regulation of bcl-2 protein expression.